nanog mailing list archives

Re: IPv6 woes - RFC


From: Mark Andrews <marka () isc org>
Date: Fri, 10 Sep 2021 18:22:34 +1000



On 10 Sep 2021, at 17:21, Bjørn Mork <bjorn () mork no> wrote:

Owen DeLong via NANOG <nanog () nanog org> writes:

The addresses aren’t the major cost of providing IPv4 services.

CGN boxes, support calls, increasing size of routing table = buying new routers, etc.

You're counting dual-stack costs as if IPv4 was the optional protocol.
That's a fantasy world.  Time to get out of la-la land now.

Your edge routers can do CGN for all connected users just fine. Yes,
there is still a cost both in resources and management, but you'll have
to weigh that against the cost of doing dual-stack on the same box.  I'm
not convinced dual-stack wins.

Don't know what you're thinking of wrt support calls, but dual-stack has
some failure modes which are difficult to understand for both end users
and support.  NAT is pretty well understood in comparison.

Your routing tables won't grow with IPv4 or CGN.  They grow when you add
IPv6.

Increased cost of developers having to work around NAT and NAT
becoming ever more complex with multiple layers, etc.

And this can be avoided by reconfiguring the local network somehow?  Or
are we talking about an Internet without IPv4?  This is even more
fantastic than the idea that IPv4 is optional in the local network.

All of these are the things driving the ever increasing cost of IPv4
services, not just the cost of the addresses.

Yes, the cost of addresses is not prohibitive, and there is no
indication it will be.

The consolidation of hosting services have reduced the need for globally
routable addresses.  You don't host your own mail server and web server
anymore, even if you're a large organisation.  Most ISPs haven't yet
taken advantage of this.  They are still giving globally routable IPv4
addresses to customers which have no need for that.  These addresses can
be re-allocated for CGN if there is a need. This is obviously still not
free, but it does limit the price of fresh IPv4 addresses.

The other costs you list will not affect an IPv4 only shop at all.


Bjørn

Or you could deliver IPv6-only to your customers and used to CGN boxes
to deliver IPv4AAS using less than 1/2 the IPv4 address space you need
for a NAT444 solution as +60% of your traffic doesn’t need CGN processing.

464XLAT example

{ Internet IPv4(40% of traffic) + IPv6(60% of traffic) } - [Router w/ NAT64] - { IPv6-only (IPv4 traffic has been 
translated to IPv6) } - [CPE w/ CLAT] { home network IPv4 + IPv6 }

DS-Lite

{ Internet IPv4(40% of traffic) + IPv6(60% of traffic) } - [Router w/ AFTR] - { IPv6-only (IPv4 traffic has been 
encapsulated in IPv6) } - [CPE w/ B4] { home network IPv4 + IPv6 }

MAP-T and MAP-E are similar to 464XLAT and DS-Lite respectively.

Yes, you have to learn something new but it costs less that a “pure" IPv4
service.

Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: marka () isc org


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